Digital data coding apparatus, DVD recording apparatus, and method of using the same

ABSTRACT

A data coding apparatus and method for recording digital data on a digital versatile disk (DVD) are provided, where the DVD recording apparatus reduces the number of times that memory is accessed by storing only additional information and parity information when ECC encoded data are temporarily stored in an external memory, and performs data coding without any clock loss by scrambling only a specific field on-the-fly when the data stored in the external memory are read.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims foreign priority under 35 U.S.C. § 119 to KoreanPatent Application No. 10-2004-0031352, filed on May 4, 2004, in theKorean Intellectual Property Office, the disclosure of which isincorporated herein in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to digital recording apparatus, and moreparticularly, to digital data coding apparatus and digital versatiledisk (DVD) recording apparatus capable of reducing the number of times amemory device is accessed in order to code digital data to be recordedon a DVD device.

2. Description of the Related Art

A DVD system generally processes data in units of data sectors,including an error correction code (ECC) block. The ECC blockfacilitates mass data transmission without errors.

Each data sector includes 12 rows of 172 bytes. A first field of thedata sector includes ID data, IED data, and CPR_MAI data, and a lastfield of the data sector includes an error detection code (EDC). An ECCblock of a DVD includes an information field having the data sector, 10bytes of parity in (PI) parity, and 16 rows of parity out (PO) parityused to correct data errors of the information field.

FIG. 1 illustrates the structure of a data sector 100 to be recorded ona DVD. Referring to FIG. 1, user data or main data to be recorded on theDVD from a host computer are classified in units of 2048 bytes. The datasector 100 comprises 4 bytes of ID data indicating address informationfor each data sector and sector power, 2 bytes of IED data that is anEDC of the ID data, and 6 bytes of CPR_MAI data indicating a reservefield or copyright management information. A first row of the datasector 100 includes 160 bytes of main data D0 through D159. Each ofsecond through eleventh rows includes 172 bytes of main data and atwelfth row includes 168 bytes of main data D1880 through D2047 and 4bytes of EDC data. Each data sector consists of 2064 bytes (2048bytes+16 bytes), that is, twelve 172-byte rows.

FIG. 2 illustrates the structure of an ECC block 200 comprising aplurality of the data sectors 100 shown in FIG. 1. Referring to FIG. 2,the ECC block 200 contains sixteen of the data sectors 100 to which ECCis added by calculating a Reed-Solomon code. The ECC block is recordedon the DVD to maintain data reliability. The ECC block is formed bycalculating a Reed-Solomon code of one block that is formed from 16 datasectors and adding ECC.

The ECC block includes 10 bytes of ECC calculated from each row of the16 data sectors in a horizontal direction, and the calculated ECC isadded to the back of each corresponding row. A column of the added ECCforms a PI parity block having a size of 10 bytes×192 rows. The ECCblock further includes 16 bytes of ECC calculated from each column ofthe data sectors and the PI parity block, and the calculated ECC isadded in a vertical direction to the bottom of each correspondingcolumn. The row of the added ECC forms a PO parity block having a sizeof (172+10) bytes×16 rows. Therefore, one digital data block to berecorded on the DVD is 182 bytes×208 rows=37,856 bytes.

An external memory device for temporarily storing data is required toprocess a signal used to code and modulate main data transmitted from ahost computer. SDRAM is used as the external memory device. Anintegrated circuit (IC) is used for coding data to be recorded to theDVD. The IC must frequently access the SDRAM in order to store the datainto the SDRAM, and in order to read and process the stored data to berecorded to the DVD.

FIG. 3 is a diagram illustrating a process of accessing external memoryin a conventional DVD recording apparatus. Referring to FIG. 3, arecording apparatus 300 for recording digital data to a DVD includes aDVD recorder IC 301 and external memory or SDRAM 303. Main datatransmitted from a host computer are stored in the SDRAM 303 at step305. The DVD recorder IC 301 accesses the SDRAM 303 32,768 times(2048×16 sectors) per data block.

The main data stored in the SDRAM 303 are read and ECC encoded at step307. The number of times when the SDRAM 303 is accessed is 2048×16sectors=32,768 times per data block at step 307, which is equal to thenumber of times for storing the main data. The DVD recorder IC 301 adds4 bytes of ID data, 2 bytes of IED data, and 6 bytes of CPR_MAI data toeach data sector, performs an EDC operation and adds the EDC. Each datasector contains 2064 bytes including 16 bytes of additional informationadded to 2048 bytes of main data. Thereafter, the data is scrambled. Thescrambled data are ECC encoded in data block units by adding 10 bytes ofPI parity to each row and adding 16 rows of PO parity to the blockcontaining the PI parity. (10×192) bytes of PI parity and (182×16) bytesof PO parity are added as shown in FIG. 2. Thus, one data block contains182 bytes×208 rows=37,856 bytes.

The encoded data are stored in the SDRAM 303 at step 309. At this time,the DVD recorder IC 301 accesses the SDRAM 303 37,856 times per datablock.

The DVD recorder IC 301 reads the data stored in the SDRAM 303 toperform eight-to-fourteen modulation (EFM) at step 311. At this time,the DVD recorder IC 301 accesses the SDRAM 303 37,856 times per datablock.

The DVD recorder IC 301 performs the EFM for the read data and recordsthe modulated data on the DVD. Digital data are recorded on the DVD at apredetermined speed. The DVD recorder IC 301 must read and store data inthe SDRAM 303, which is an external buffer memory, within a designatedtime.

However, as DVD recording apparatuses record data at higher speeds, therate at which data is to be accessed from the external buffer memorymust be increased. Therefore, when mass data are recorded on a DVD-RAMat high speed, it is important to reduce the number of times theexternal buffer memory is accessed with a disk recording speed of hightransmission rate.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present disclosure provide high-speeddigital versatile disk (DVD) recording apparatus and methods of usingthe same in which the number of times a DVD recorder IC accesses anexternal buffer memory can be reduced.

A preferred embodiment of the present disclosure provides a DVDrecording apparatus and a method using the same by which a whole DVDrecorder system can obtain a bandwidth gain when the DVD recorder systemis implemented as a system on chip (SOC).

According to an aspect of the present disclosure, there is provided amethod of recording data on a DVD, the method comprising: recording maindata to be recorded on the DVD in a memory device; reading the recordedmain data from the memory device to error correction code (ECC) encodethe main data; ECC encoding and scrambling the main data; recordingadditional address information and parity information included in theECC encoded and scrambled data except the main data to the memorydevice; and reading the address information, the parity information, andthe main data stored in the memory device and scrambling the read datato perform eight to fourteen modulation (EFM) on the main data.

The additional address information and the parity information mayinclude an ID, error detected code (EDC) of the ID (IED), CPR_MAI, EDCparity, and ECC parity except the main data.

The scrambling of the main data is performed on-the-fly and the readingof the address information, the parity information, and the main dataand the scrambling of the main data on-the-fly are performedsimultaneously.

According to another aspect of the present disclosure, there is provideda method of coding digital data to be recorded on a DVD, the methodcomprising: recording main data to be recorded on the DVD in a memorydevice; reading the recorded main data from the memory device to ECCencode the main data; ECC encoding and scrambling the main data;recording additional address information and parity information includedin the ECC encoded and scrambled data except the main data to the memorydevice; and reading the address information, the parity information, andthe main data stored in the memory device and scrambling the read datato perform EFM on the main data.

According to another aspect of the present disclosure, there is providedan apparatus for recording digital data on a DVD, the apparatuscomprising: a memory device for temporarily storing data to be recordedon the DVD; an ID generation circuit for adding an ID and IED of the IDfor each of a plurality of data sectors; an EDC generation circuit foradding EDC of the data to each of the data sectors; a first scramblecircuit for scrambling the data in data sector units; an ECC encodingcircuit for adding PI parity and PO parity to the scrambled data insector units and ECC encoding the added data; and a second scramblecircuit for separately reading main data, the ID, IED, EDC parity, andECC parity from the memory device and scrambling the read data, whereinadditional information besides the main data included in the ECC encodedand scrambled data is stored in the memory device and, when the maindata are read from the memory device to perform EFM on the main data,the address information, the parity information and the main data storedin the memory device are read and scrambled by the second scramblecircuit.

The second scramble circuit scrambles the main data field on-the-fly andreads the main data and the ID, IED, EDC parity and ECC paritysimultaneously.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present disclosurewill become more apparent by describing in detail exemplary embodimentsthereof with reference to the attached drawings, in which:

FIG. 1 is a schematic diagram that illustrates the structure of a sectorof digital data to be recorded on a digital versatile disk (DVD);

FIG. 2 is a schematic diagram that illustrates the structure of an ECCbock comprising a plurality of the data sectors shown in FIG. 1;

FIG. 3 is a schematic diagram illustrating a process of accessingexternal memory in a conventional DVD recording apparatus;

FIG. 4 is a schematic diagram illustrating a process of accessingexternal memory in a DVD recording apparatus according to an embodimentof the present disclosure; and

FIG. 5 is a block diagram of a DVD recording apparatus according to anembodiment of the present disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, the present disclosure is described more fully withreference to the accompanying drawings, in which embodiments of thedisclosure are shown. Like reference numerals in the drawings may denotelike elements.

FIG. 4 shows a process of accessing external memory in a DVD recordingapparatus according to an embodiment of the present disclosure.Referring to FIG. 4, a DVD recording apparatus and method 400 forrecording digital data on a DVD includes a DVD recorder integratedcircuit (IC) 401 and an external buffer memory or SDRAM 403. The DVDrecorder IC 401 receives data transmitted from a host computer andstores the received data in the SDRAM 403 at step 405. The DVD recorderIC 401 accesses the SDRAM 403 32,768 times (2,048×16 sectors) per datablock at step 405.

The DVD recorder IC 401 reads main data stored in the SDRAM 403, addsvarious pieces of additional information to the read main data, andscrambles and ECC encodes the added data at step 407. To this end, theDVD recorder IC 401 accesses the SDRAM 403 32,768 times (2,048×16sectors) per data block, which is equal to the number of times the DVDrecorder IC 401 accesses the SDRAM 403 to store the data.

The DVD recorder IC 401 adds 4 bytes of ID data, 2 bytes of IED data,and 6 bytes of CPR_MAI data to each data sector and performs an EDCoperation and adds the EDC. Each data sector contains 2,064 bytesincluding 16 bytes of additional information added to 2,048 bytes ofmain data. Thereafter, the data is scrambled. The scrambled data are ECCencoded in units of data blocks by adding 10 bytes of PI parity to eachrow and adding 16 rows of PO parity to the block containing the PIparity. (10×192) bytes of PI parity and (182×16) bytes of PO parity areadded as shown in FIG. 2. Thus, one data block contains 182 bytes×208rows=37,856 bytes.

Among the encoded data, additional information other than main data isstored in the SDRAM 403 at step 409, where the additional informationincludes ID data, IED data, CPR_MAI data, EDC parity and ECC parity. Atthis time, the DVD recorder IC 401 accesses the SDRAM 403 5,088 timesper data block ((4+2+4+6)×16 bytes comprising ID data, IED data, CPR_MAIdata, EDC data)+10×192 (PI parity)+182×16 (PO parity)). Therefore, thenumber of times the SDRAM 403 is accessed is reduced by 12% by storingonly additional information rather than all encoded data.

The DVD recorder IC 401 reads the main data and the additionalinformation stored in the SDRAM 403 and ECC parity information toperform eight to fourteen modulation (EFM) at step 411. At this time,the DVD recorder IC 401 can scramble only a main data field on-the-flysimultaneously while reading the main data, additional information, andECC parity information, thereby obtaining a reading result equal to aconventional result without any clock loss. In addition, the DVDrecorder IC 401 can determine an initial value of a scramble linearfeedback shift register (LFSR) while reading the ID information.

At this time, the DVD recorder IC 401 accesses the SDRAM 403 37,856times per data block. The DVD recorder IC 401 performs the EFM for theread data and records the modulated data on the DVD.

FIG. 5 is a block diagram of a DVD recording apparatus according to anembodiment of the present disclosure, which is indicated generally bythe reference numeral. Referring to FIG. 5, the DVD recording apparatus500 comprises a DVD recorder IC 501, a host 503, and an external memory505.

The DVD recorder IC 501 receives digital data from the host 503, codesthe received digital data, and records the coded digital data on a DVD507. The external memory 505 temporarily stores digital data while theDVD recorder IC 501 codes the received digital data.

The DVD recorder IC 501 includes an ID+IED generation circuit(hereinafter, referred to as an ID generation circuit) 511, an EDCgeneration circuit 513, an I/F circuit 515, a first scramble circuit517, an ECC generation circuit 519, a second scramble circuit 521, andan EFM circuit 523.

The ID generation circuit 511 generates ID information, EDC of the IDinformation (IED data), and copyright information (CPR_MAI data) in datasector units. The EDC generation circuit 513 generates the EDC of datain data sector units. The I/F circuit 515 provides an interface betweenthe DVD recorder IC 501 and external devices 503 and 505 totransmit/receive data.

After additional information is added to the data and the added data areECC encoded, the I/F circuit 515 stores only additional information andECC parity information in the external memory 505.

The first scramble circuit 517 scrambles the main data in data sectorunits read from the external memory 505. The ECC generation circuit 519receives the scrambled data and the information on ID, IED, CPR_MAI andEDC, combines the additional information with the main data, divides thecombined data into bit streams with a predetermined length, andgenerates and adds the EDC of the bit stream divided into the bitstreams with the predetermined length.

When the DVD recorder IC 501 separately reads the additional informationincluding the main data, the ID information, and the ECC parity, thesecond scramble circuit 521 scrambles a predetermined field, i.e., themain data field, on-the-fly and transmits the scrambled data to the EFMcircuit 523. The EFM circuit 523 modulates the 8-bit scrambled data into14-bit data and outputs the modulated data to the DVD 507.

Referring to FIGS. 4 and 5, a digital data recording operation is nowdescribed. The host 503 transmits user digital data, i.e., main data, tobe recorded on the DVD 507 to the DVD recorder IC 501. The DVD recorderIC 501 temporarily stores the main data in the external memory 505. Thefirst scramble circuit 517 combines the main data read from the externalmemory 507 with the ID, the IED, the CPR_MAI and the EDC paritygenerated by the ID generation circuit 511 and the EDC generationcircuit 513, and scrambles the combined data. The ECC generation circuit519 performs an ECC operation and adds the ECC to the scrambled data tomaintain reliability of the digital data. The data generated by the ECCgeneration circuit 519 consists of sixteen data sectors or one datablock to generate ECC parity.

Meanwhile, when the ECC encoded data are temporarily stored in theexternal memory 505, the external memory 505 does not store all theencoded data, but only the additional information and the parity, andnot the main data.

When the DVD recorder IC 501 reads data from the external memory 505again to perform the EFM of the digital data, it scrambles a specificfield, i.e., only a main data field, by an on-the-fly method, whilereading the main data, the additional information, and the parityinformation. At this time, the DVD recorder IC 501 can determine aninitial value of the scramble LFSR while reading the ID information.

The number of times the recording apparatus 500 accesses the externalmemory 505 can be considerably less than the number of times aconventional recording apparatus accesses an external memory. The secondscramble circuit 521 makes it possible to obtain the same data codingresult as the conventional data coding result without any clock lossusing the on-the-fly method.

In the DVD recording apparatus and the DVD recording method shown inFIGS. 4 and 5, a digital data coding apparatus and a digital data codingmethod to record digital data on a DVD are provided.

The circuit shown in FIG. 5 can be implemented as one chip, i.e., asystem on chip (SOC), thereby reducing the number of times the externalmemory 505 is accessed and increasing the bandwidth of a whole recordingsystem.

The digital data coding method and the digital data recording methodmake it possible to reduce the number of times an external memory isaccessed and implement a high-speed DVD recording system. When the DVDrecording system is implemented as a SOC, the number of times theexternal memory is accessed is reduced to increase the bandwidth of thesystem.

While the present invention has been particularly shown and describedwith reference to exemplary embodiments thereof, it will be understoodby those of ordinary skill in the pertinent art that various changes inform and details may be made therein without departing from the spiritand scope of the present invention as defined by the following claims.

1. A method of recording data on external media, the method comprising:recording unencoded main data to a memory device; reading the recordedmain data from the memory device; encoding the read main data with anerror correction code (ECC); scrambling the encoded main data to provideaddress and parity information; recording the address and parityinformation, but not the encoded main data, to the memory device;reading the address and parity information and the unencoded main datafrom the memory device; and scrambling the unencoded main data toperform eight-to-fourteen modulation (EFM) on the main data.
 2. Themethod of claim 1, wherein the external media comprises a digitalversatile disk (DVD).
 3. The method of claim 2, further comprising:performing EFM on the scrambled unencoded main data; and storing the EFMmodulated data in the DVD.
 4. The method of claim 1, wherein the addressand parity information includes an ID, error detected code (EDC) of theID (IED), CPR_MAI, EDC parity and ECC parity, but not the main data. 5.The method of claim 4, wherein the ECC encoding comprises dividing themain data into bit streams containing 2048 bytes each and adding 4 bytesof ID data indicating address information of each sector and sectorpower, 2 bytes of IED data that is EDC for the 4 bytes of ID data, 6bytes of CPR_MAI data indicating copyright management information, and 4bytes of EDC to each bit stream to form one data sector.
 6. The methodof claim 5, wherein the ECC encoding further comprises adding parityinner (PI) parity information to each sector and adding parity outer(PO) parity information to sixteen of the data sectors and to the PIparity information to form one data block.
 7. The method of claim 1,wherein the memory device is an SDRAM memory device.
 8. The method ofclaim 1, wherein scrambling the unencoded main data is performedon-the-fly and simultaneously with reading the address and parityinformation and the unencoded main data from the memory device.